View Code of Problem 2217

#include <iostream>
#include <string>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <queue>
using namespace std;

int main()
{
	int n, m, t;
	int i, j, k;
	int p,c;
	while (cin >> m >> n >> p >> c) 
	{
		if (m == 0 && n == 0 && p == 0 && c == 0)
			break;
		cout << m + p - n << endl;
	}
	return 0;
}